Predictive value of noninvasively determined endothelial dysfunction for long-term cardiovascular events and restenosis in patients undergoing coronary stent implantation: a prospective study

Background Endothelial dysfunction plays a key role in atherosclerosis and predicts future cardiovascular events in individuals with or without coronary artery disease and improves with risk reduction therapy. We sought to determine the predictive value of endothelial dysfunction for long-term cardiovascular events and in-stent restenosis in patients undergoing percutaneous coronary intervention (PCI). Methods Using high-resolution ultrasound, we assessed endothelial function by using the brachial artery flow-mediated dilation (FMD) method in 135 patients with coronary artery disease before elective coronary stenting. Patients were prospectively followed up for an average of 12 months after PCI. Results Thirty patients had an event during follow-up including cardiac death (four patients), myocardial infarction (nine patients), unstable angina/non-ST elevation myocardial infarction (15 patients), and stroke (two patients) and in-stent restenosis was determined in 16 of these patients. Endothelium-dependent FMD was significantly lower in patients who had an event compared with those without an event (4.7 +/- 1.9 vs. 6.0 +/- 2.0%, P=0.007), whereas endothelium-independent vasodilation to nitroglycerin was similar in both groups. FMD was the only predictor of cardiovascular events (P=0.03). Impaired endothelial function was associated with a significantly higher incidence of cardiovascular events and in-stent restenosis by Kaplan-Meier analysis. When a cutoff point of 7.5% was used, flow-mediated dilation had a sensitivity of 93%, specificity of 37%, and negative predictive value of 95% for cardiovascular events. Conclusion Impaired brachial artery FMD is associated with long-term cardiovascular events and in-stent restenosis in patients undergoing PCI. Noninvasive assessment of endothelial function may serve as a surrogate marker for the estimation of future cardiovascular event risk and long-term follow-up in these patients.